Display screen or a portion thereof with transitional graphical user interface



FIG. 1 is a front view of a first image in a sequence for a display screen or a portion thereof with transitional graphical user interface, showing our new design;

FIG. 2 is a front view of a second image thereof;

FIG. 3 is a front view of a third image thereof; and,

FIG. 4 is a front view of a fourth image thereof.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1 through 4. The subject matter of this patent includes a process or period in which an image changes into another image. This process or period forms no part of the claimed design.

The broken line drawing of the portion of the display screen shown in FIGS. 1 through 4 forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or a portion thereof with transitional graphical user interface, as shown and described. 